Touch screen for mobile telephone

ABSTRACT

A touch screen arrangement fitted to a mobile telephone apparatus and built-on or resting on a substrate. The touch screen includes a display unit and a number of light pulse emitting units and a number of light pulse receiving units, said units being edge-related to said display unit. The light pulse emitting units and the light pulse receiving units are orientated adjacent said display unit, with the directions of said emitted and received light pulses being at right angles, or at least generally at right angles, to a planar surface on the display unit. The touch screen also includes four light pulse deflecting devices positioned close to the display surface.

This application is the US national phase of international applicationPCT/SE02/02000 filed in English on 4 Nov. 2002, which designated the US.PCT/SE02/02000 claims priority to SE Application No. 0103835-5 filed 2Nov. 2001. The entire contents of these applications are incorporatedherein by reference.

FIELD OF INVENTION

The present invention relates generally to a display arrangement, thatis formed onto or is supported by a substrate, and more particularly toa mobile-telephone-adapted touch screen arrangement, which isconstructed with and around a display unit, whose external dimensionsconform with those applicable to mobile telephone apparatus or cellphones.

The touch screen arrangement is hereinafter abbreviated to “touchscreen”.

DESCRIPTION OF THE BACKGROUND ART

Mobile telephone displays normally consist of an LCD unit and anassociated keypad, where depression of a key activates one or moretelephone functions.

It can be mentioned with regard to known technology, that the use of atouch screen has been proposed with regard to hand-carried computerterminals, with the intention of reducing the dimensions of a displaysurface, wherein selected functions can be activated through the mediumof visible digits or other symbols, by exerting pressure on a surfacesection corresponding to the surface section of the symbol concerned,with the aid of a pointer.

Touch screens, or touch sheets, of this kind have been produced in theform of two mutually parallel plastic sheets, where a mechanicalactuation of an uppermost sheet within a chosen surface section createsconditions for a resistance measurement perpendicular to said surfacesection, wherein the geographical position of said surface section onthe touch screen can be established by a calculating circuit, with theaid of the resistance values established, and therewith generate asignificant signal for a function related to a touched symbol.

In this case, there is used a hand-held and hand-maneuvered elongatepointer having a tip, comparable to that of a pencil or pen, whichrequires physical actuation on and pressure against the chosen surfacesection of the display unit.

Also known to the art are touch screens that have relatively largeexternal dimensions, where the dimensions chosen and a chosen screenthickness are of small account and constitute no limitation to thechosen application.

For example, it is known in respect of this use application to allow thetouch screen to be comprised of a display unit in the form of an LCDunit, with edge-orientated and mutually opposite light-emitting unitsand light receiving units.

More particularly, in the case of this application the light-emittingunits and the light receiving units are orientated in two rows and twocolumns over the upper surface of the display unit, with thetransmitting and receiving directions of the light rays orientated anddirected immediately above the upper surface of the display unit, withsaid units directly opposite each other.

Light emitting circuits and light receiving circuits are also mutuallycoordinated and connected to a calculating or computing unit in thiscase, so as to evaluate and calculate a position representative of thegeographical position on the upper surface of the display unit, wheremutually intersecting light rays are shadowed by an object serving as apointer, depending on the position of one or more coordinate-orientatedlight receiving units, having associated circuits which are intended toindicate the presence of light.

It is known in the case of this latter application to use the tip of anindex finger as a pointer, and no physical actuation of or pressureagainst said display surface section is required in this particulartechnique, even though such is usual.

The contents of the patent publications listed below also belong to theearlier standpoint of techniques with regard to the use of a touchscreen, in which light emitting and light receiving units and the tip ofan index finger or the like function to activate signals correspondingto a chosen symbol presented on a surface section of the displaysurface.

U.S. Pat. No. 4,847,606

This publication illustrates and describes a control system (10), whichin addition to a display panel (22) comprised of liquid crystals alsoincludes a light source (20) and a light detector (36).

More specifically, the publication is concerned with allowing light fromthe light source to be directed through at least part of the liquidcrystal display panel and onto the light detector.

The system (10) includes a casing (12), which is formed to be fitted tothe instrument panel of a car, said panel including a sunken surfacepart (14) and being produced from a transparent material.

A casing part (18) is adapted to enclose the components related to thecontrol system (10).

The light source (20) is illustrated in the form of a fluorescent lampand is adapted to extend across the full width of the casing.

Light is able to pass through a number of “windows” (24) in the panel(22) and is reflected through 90 degrees by a mirror surface (26).

The light shall then pass a transparent casing-wall portion (28), andthen through the sunken surface portion (14), and thereafter through anopposite wall portion (32), so as to be reflected onto the lightdetector or light receiver (36) by a mirror surface (34).

FIG. 1 of this patent publication shows that when a fingertip (49) isplaced within the sunken surface (14), a number of light rays areshadowed within a defined area (48 a), enabling this area to bedetected.

FIG. 8 shows a system in which light sources and light detectors orlight receivers are orientated in perpendicular co-ordinates.

U.S. Pat. No. 4,880,969

This patent publication describes and illustrates a programmable touchscreen.

FIGS. 3 and 4 in particular illustrate an optical keyboard (12) whichincludes an IR-adapted light source (32), a light receiver (34) andoptical “prism” or mirror surfaces (36, 38).

In this regard, FIG. 3 shows that these mirror surfaces (36, 38) arerelated to mutually opposite edge portions of a window surface (22).

EP-A1-0 330 767

This publication illustrates and describes a touch screen, which isadapted to create control signals by means of which a function can beselected in response to the movement and displacement of an operatorsfingertip relative to the screen (1).

More particularly, this publication is concerned with the activation ofa time circuit immediately when a finger or a fingertip touches thetouch screen, where a particular movement direction and a particulardistance of movement are detected and an electronic unit or the like isactivated in response to these parameters.

The touch screen or touch panel (1) is provided along its four sideswith light-emitting diodes (LED) (101-114) and light receiving devicesin the form of phototransistors or photodiodes (201-214), as illustratedin FIG. 2.

The finger or the fingertip shadows one or more light beams orientatedin a right-angled co-ordinate system, wherein shadowed light receivingdevices and detected changes in shaded devices constitute magnitudesfrom which desired functions are evaluated and initiated.

SUMMARY OF THE INVENTION Technical Problems

When taking into consideration the technical deliberations that a personskilled in this particular art must make in order to provide a solutionto one or more technical problems that he/she encounters, it will beseen that it is necessary, on the one hand, to realise initially themeasures and/or the sequence of measures that must be undertaken to thisend, and on the other hand to realise which means is/are required tosolve one or more of said problems. On this basis, it will be evidentthat the technical problems listed below are highly relevant to thedevelopment of the present invention.

When considering the earlier standpoint of techniques, as presented inthe afore going, it will be seen that a technical problem resides in theability to create conditions which enable a mobile telephone apparatus,or cell phone, to be provided with a touch screen that includesedge-related light-emitting units and oppositely located edge-relatedlight receiving units together with associated circuits while retainingthe small external dimensions of said apparatus, so that a geographicalsurface section and a function corresponding to said surface section canbe established through the medium of a calculating unit, or computingunit, when certain light pulse receiving units do not indicate thereception of expected light pulses.

Another technical problem resides in the ability to create constructioninstructions that will provide conditions for reducing the spacerequired by such a touch screen and for adapted planning and placementof said screen within the external confines of a mobile telephone.

A further technical problem resides in the ability to create conditions,with the aid of simple means, that enable energy consumption and powerrequirements to be kept low, with regard to the mobile telephone beingbattery powered, by generating short light pulses and by allowing theunits to be activated sequentially in a chosen order.

In the case of this latter application, it will be seen that a technicalproblem resides in allowing the use of a number of pulse generatingcircuits, each connected to a respective light pulse emitting unit, anda number of light pulse receiving units, each connected to a respectivepulse receiving circuit, and in the ability to establish, via acalculating unit, the geographic position of a user's fingertip, orthumb tip, on a front surface part, positioned so as to shadow one ormore parallel, related light pulses and therewith indicate the absenceof light pulses in one or more light pulse receiving units andunit-related pulse-receiving circuits.

When considering the earlier standpoint of techniques as describedabove, it will also be seen that a technical problem resides in theprovision of structural changes in a touch screen, such as to enable thescreen to be significantly thinner than prior art screens, so as toadapt said screen directly onto a mobile telephone.

A further technical problem resides in the ability to provide a touchscreen, with which, in respect of other external dimensions of saidscreen, it is possible to create conditions which enable the externalmeasurements of a mobile telephone unit to be reduced while,nevertheless, enabling the width of the display surface of a displayunit to be made larger than the display surface of known mobiletelephone units.

A further technical problem resides in the ability to realise thesignificance of and the advantages associated with allowing an inventivetouch screen to be used as an alternative, not solely for a typicalkeypad but also for a standard display surface of a mobile telephone.

Another technical problem resides in the ability to realise thesignificance of and the advantages afforded by utilising a display unitin the form of an LCD unit, so as to enable each “key” to be included onthe screen in the form of a graphic, so that when a pen, pencil, fingeror a fingertip is placed on the same location or surface section where akey is presented, a chosen function and/or application corresponding tosaid graphic is activated and generated.

Still another technical problem resides in the ability to realise thesignificance of and the advantages afforded by using an LCD unit, whoseupper surface can be allocated different information carrying structuresaccording to a chosen menu, for different sequences within aninformation transmitting mode.

Another technical problem resides in the ability to realise thesignificance of and the advantages associated with orientating saidlight pulse emitting units and said light pulse receiving units adjacentsaid display unit, with the transmitting and receiving directions of thelight pulses being perpendicular to, or at least generally perpendicularto, a flat upper surface of the display unit.

Yet another technical problem resides in the ability to realise thesignificance of and the advantages associated with placing at least two,normally four, pulse-deflecting devices close to the display unit and toits mutually opposite edge portions.

Another technical problem resides in the ability to realise thesignificance of and the advantages associated with using as a supportivesubstrate a mobile telephone printed circuit board, that is capable ofcarrying an LCD unit or the like.

A further technical problem resides in the ability to realise thesignificance of enabling a substrate to support not only said displayunit but also said light pulse emitting and light pulse receiving units,where said light pulses have a frequency within the infrared range (IRrange).

Another technical problem resides in the ability to realise thesignificance of and the advantages afforded by enabling said light pulseemitting units and said light pulse receiving units to be connected tocorresponding pulse generating circuits and pulse receiving circuitsincluded in said substrate, through the medium of connection wires orthe like.

Another technical problem resides in the ability to realise thesignificance of and the advantages afforded by allowing the lightdeflecting devices or light pulse deflecting devices to consist of aplurality of mirror units, co-ordinated with the casing of the mobiletelephone unit.

Another technical problem resides in the ability to realise thesignificance of and the advantages associated with allowing said lightpulse deflecting devices to consist of four mirror units, with theirmirror surfaces orientated at 45 degrees in relation to the propagationdirection of the light pulses, from said angled light pulse generatingunits and to said angled light pulse receiving units.

A further technical problem resides in the ability to realise thesignificance of and the advantages associated with allowing said lightpulse deflecting devices to consist of a separate right-angledequilateral, three-sided and right-angled prism unit, having a lightpulse deflecting mirror surface, or a corresponding means.

Another technical problem resides in the ability to realise thesignificance of and the advantages afforded by enabling a circuit boardor a printed circuit board to carry electronic circuits and componentsadapted for carrying out functions related to the mobile telephone unitand/or to an associated mobile telephone network.

Another technical problem resides in the ability to realise thesignificance of and the advantages associated with allowing said lightpulse emitting units and said light pulse receiving units to beorientated in respective rows and respective columns, with mutualperpendicular orientations and with a distance between said rows orcolumns that only slightly exceeds the dimensions chosen with respect tosaid display unit.

Another technical problem resides in the ability to realise thesignificance of and the advantages associated with allowing said circuitboard carrying, inter al, said display unit, said light pulse emittingunits, said light pulse receiving units and fixed components necessaryto the function of the mobile telephone unit, to be adapted forattachment to a part of the complete casing of the mobile telephoneunit.

Another technical problem resides in the ability to realise thesignificance of and the advantages afforded by fastening the edges ofsaid light pulse deflecting devices along the raised rim portions of arecess in a casing part in the form of a replaceable lid, where said rimand said rim portions co-act with a transparent protective means, suchas a plastic sheet.

In respect of certain conditions where a plurality of side-related lightpulse receiving units and their associated pulse receiving circuits alsoindicate the absence of light pulses, another technical problem residesin the ability to realise the significance of and the advantages thatare afforded by adapting the calculating unit to interpret thisinformation, with the aid of internal computing circuits, as meaningthat the intended geographical position shall be considered to belocated between outer points representative of said pulse receivingcircuits that indicate the absence of light pulses.

In respect of certain conditions where a plurality of angled andside-related light pulse receiving units and associated pulse receivingcircuits indicate, at the same time, the absence of light pulses,another technical problem resides in the ability to realise thesignificance of and the advantages afforded by adapting the calculatingunit to interpret this information, with the aid of internal computingcircuits, as meaning that the intended geographical position shall beconsidered to be located between outer points representative of saidpulse receiving circuits that indicate the absence of light pulses.

Another technical problem resides in the ability to realise thesignificance of and the advantages afforded by allowing said light pulseemitting units to be activated, through the medium of associated pulsegenerating circuits, either sequentially or in chosen positions in apredetermined order, and by allowing the corresponding light pulsereceiving units and their pulse receiving circuits to be also activatedin said predetermined order.

A further technical problem resides in the ability to realise thesignificance of and the advantages afforded by adapting a plurality oflight pulse emitting units to emit light pulses consecutively over achosen time duration, and by adapting one single light pulse receivingunit to be activated, via its pulse receiving circuit, so as to receiveexpected light pulses during said chosen time duration and therewithallow registration of occurring light pulses and/or shadowed lightpulses or the absence of light pulses.

Another technical problem resides in the ability to realise thesignificance of and the advantages afforded by adapting a plurality oflight pulse receiving circuits so that light pulses emitted from asingle light pulse emitting unit can be received consecutively duringsaid time duration, and by adapting the light pulse receiving units sothat said units will be active, via pulse receiving circuits, duringsaid chosen time duration for receiving expected light pulses andtherewith allow registration of occurring light pulses and/or shadowedlight pulses or the absence of light pulses.

Solution

The present invention takes as its starting point the known technology,as it is described above, and is based on a touch screen arrangement,which is built on or rests on a supportive substrate, and which isadapted for a mobile telephone apparatus or set and incorporated in theapparatus with the aid of a known display unit.

With the intention of solving one or more of the aforesaid technicalproblems related directly to mobile telephone apparatus or sets, theinvention proposes the use of an arrangement, constructed in principlein accordance with what is used and proposed within other technicalfields, said arrangement comprising a number of light pulse emittingunits together with a number of oppositely located light pulse receivingunits, said units both being edge-related to the display unit of saidmobile telephone.

The light pulse emitting units are adapted to send light pulsessequentially through a short distance over the upper surface of adisplay unit, via associated pulse generating circuits, said uppersurface presenting a graphic, such as rows and columns of geographicallydisposed symbols, such as letters, numbers and/or correspondinggraphics.

The light pulse receiving units are adapted to receive light pulsessequentially, and each of the pulse receiving circuits and pulseemitting circuits are coordinated and connected to a calculating orcomputing unit.

The calculating unit will include calculating circuits, that function toevaluate a position representative of the geographical position on theupper surface of the display unit where light rays, such as intersectinglight rays, are shadowed by a pointer, such as the front surface part ofa users thumb, depending on the position of one or more co-ordinateorientated light pulse receiving units and their associated pulsereceiving circuits that should indicate the presence of a light pulse.

By way of proposed embodiments, that lie within the scope of the presentinvention, it is particularly proposed that said light pulse emittingunits and said light pulse receiving units are orientated adjacent saiddisplay unit, with the light pulse emitting and light pulse receivingdirections being at right angles, or at least generally at right angles,to a planar upper surface of the display unit.

Also proposed is the use of a number of light pulse deflecting devices,such as four devices, that are orientated close to the display unit andthat function to cause mutually intersecting light pulses to passparallel across the upper surface of the display unit.

By way of proposed embodiments that lie within the scope of theinventive concept, it is also proposed that a supportive substrate iscomprised of a circuit board or printed circuit board of the mobiletelephone unit.

In addition to carrying the display unit, the substrate is also adaptedto carry said light pulse emitting and light pulse receiving units.

The light pulse emitting units and the light pulse receiving units areconnected to said pulse generating circuits and said pulse receivingcircuits coordinated on the supportive substrate, by connecting wires orthe like.

Each of the light pulse deflecting devices may comprise a mirror unit,or a mirror portion, carried by the casing to provide a correspondingeffect.

The light pulse deflecting devices may comprise mirror units that havemirror surfaces or casing-carried mirror surfaces orientated at 45degrees in relation to the direction of propagation of the light pulsesemitted by said light pulse emitting units towards said light pulsereceiving units.

The light pulse deflecting devices may also comprise a right-angledequilateral, three-sided and right-angled prism unit.

The circuit board or printed circuit board, that functions as asubstrate, may also support electronic circuits and components adaptedto perform functions related to the mobile telephone unit or set.

The light pulse emitting units and the light pulse receiving units areorientated in two rows and two columns of mutual perpendicularorientations, with a distance between said rows and columns that onlyslightly exceeds corresponding dimensions of said display unit.

It is also proposed that the circuit board or printed circuit board thatincludes, inter al, display units, light pulse emitting units, lightpulse receiving units, and fixed components, necessary to carry out thenormal functions of the mobile telephone unit, is adapted to enable itto be fastened to or against part of the casing of the mobile telephoneunit.

The light pulse deflecting devices are fastened, edge-orientated, alongthe raised rims of a replaceable lid or cover, said rims, or parts ofsaid rims, co-acting with and supporting a transparent protectivedevice, such as a plastic or glass sheet.

It is also proposed in accordance with the invention that conditions areprovided whereby, when a plurality of side-related light pulse receivingunits and their associated pulse receiving circuits indicatesimultaneously the absence of light pulses, the calculating unit willinterpret this information, with the aid of internal calculatingcircuits, as indicating that the intended geographical position shall beconsidered to be located at or between points representative of saidlight pulse receiving units, as an indication of the absence of lightpulses.

In respect of conditions where a plurality of angled and side-relatedlight pulse receiving units, and their associated pulse receivingcircuits, simultaneously indicate the absence of light pulses, thecalculating unit functions, with the aid of internal calculatingcircuits, to interpret this information to mean that the intendedgeographical position shall be considered to be located at one point orbetween points representative of said light pulse receiving units thatindicate the absence of light pulses.

It is also proposed that when said light pulse emitting units areactivated, via associated pulse generating circuits, either sequentiallyor positioned selectively in a predetermined order, the correspondingpulse receiving circuits shall also be capable of being activated in thesame predetermined order.

A plurality of light pulse emitting units may be adapted toconsecutively emit light pulses with the aid of said pulse generatingcircuits over a chosen time duration, wherein one single light pulsereceiving unit is adapted to be activated to receive anticipated lightpulses during said chosen time duration and therewith allow occurringlight pulses and/or shaded light pulses or the absence of light pulsesto be registered through the medium of an associated pulse receivingcircuit.

A plurality of light pulse receiving units may be adapted to receivelight pulses emitted from one single light pulse emitting unitconsecutively during a chosen time period, wherein each of the lightpulse receiving units is adapted to be activated, via associated pulsereceiving circuits, to receive light pulses during said chosen timeperiod and therewith allow occurring light pulses and shadowed lightpulses and/or the absence of light pulses to be registered.

ADVANTAGES

Those advantages primarily characteristic of the present invention andthe particular significant characteristics of said invention reside inthe creation of conditions, which enable the creation of a touch screenarrangement for a mobile telephone apparatus or telephone unit or set onthe basis of the technology described in the introduction, whereinedge-related light pulse emitting units and light pulse receiving unitsadjacent associated light pulse deflecting devices may be mountedadjacent the edge surfaces of a display unit or an LCD unit, and also inthat the touch screen can thereby be given a particularly thin design,with low energy consumption and a limited power input.

More particularly, the invention makes possible clear evaluation of asmall chosen surface section of a small display surface with the aid ofthe front surface part of a thumb, said surface part covering a surfacesection that greatly exceeds the small chosen surface section.

The primary characteristic features of the present invention are setforth in the characterising clause of the accompanying claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment at present preferred and including significantcharacteristic features of the present invention will now be describedin more detail by way of example and with reference to the accompanyingdrawings, in which;

FIG. 1 is an exploded perspective view of a touch screen constructed inaccordance with the invention and placed in a mobile telephone set;

FIG. 2 illustrates in side view and in a section, taken on the lineII-II in FIG. 1, a mobile telephone set and a touch screen assembly;

FIG. 3 is a section view, according to FIG. 2, and shows a narrowpointer resting on the upper surface of a display unit for shadowing alight pulse;

FIG. 4 illustrates an example of pulse-form activation of the lightpulse emitting and light pulse receiving units used, through the mediumof pulse generating and pulse receiving circuits belonging to saidunits;

FIG. 5 is a horizontal view of a mobile telephone set that uses a touchscreen in accordance with the present invention, and shows a narrowpointer positioned to rest on a surface section of the display unit,said section corresponding to a graphic symbol in the form of the number“3”;

FIG. 6 is a schematic view of a planar display unit which is surroundedby a number of light pulse emitting and light pulse receiving unitsdisposed in right-angle co-ordinates, in which a well-defined geographicpoint is shown to give a pronounced pulse shadow or the absence of lightpulses in respect of two mutually perpendicular light pulse receivingunits;

FIG. 7 illustrates an embodiment in which a large and diffuse geographicpoint creates a pulse shadow for at least two light pulse receivingunits orientated at right angles and in pairs;

FIG. 8 illustrates an alternative embodiment for evaluating a geographicposition valid for a geographic point;

FIG. 9 illustrates a practical application of the principles indicatedin FIG. 6 for activating a “key” or “button”; and

FIG. 10 illustrates a further practical application of the principlesindicated in FIG. 6 for activating another key or button for activationof a mobile telephone function.

DESCRIPTION OF EMBODIMENTS AT PRESENT PREFERRED

It is pointed out initially that we have chosen to use in the followingdescription of embodiments at present preferred and includingsignificant characteristic features of the invention and illustrated inthe figures of the accompanying drawings special terms and terminologywith the intention of illustrating the inventive concept more clearly.

However, it will be noted that the expressions chosen here shall not beseen as limited solely to the chosen terms used in the description, butthat each term chosen shall be interpreted as also including alltechnical equivalents that function in the same or at least essentiallythe same way so as to achieve the same or essentially the same intentionand/or technical effect.

FIG. 1 thus illustrates schematically an embodiment and an applicationof the present invention, said figure concretising generally thesignificant properties of the embodiment described in more detail below.

Thus, FIG. 1 is a perspective exploded view of a mobile telephoneapparatus T whose casing parts 10, 11 enclose a touch screen arrangement1, that rests on a supportive “substrate” 2, among other things.

The supportive substrate 2 of the illustrated embodiment has the form ofa printed circuit board or a circuit board 2′ of known design.

FIG. 1 is an exploded view of a mobile telephone apparatus T thatincludes a display unit 3 and edge-orientated light pulse emitting units4 and oppositely located edge-orientated light pulse receiving units 5,which extend along respective sides of said display unit 3.

Although not shown, the “substrate” 2 may include edges that are raisedfrom a display unit 3, in the form of a known LCD unit.

It is obvious that the basic principles of the present invention can beimplemented solely with the use of rows or columns of light pulseemitting units 4 and oppositely located rows or columns of light pulsereceiving units 5 with respective associated circuits 4 a and 5 a, atleast with respect to the activation of certain functions.

It will be understood, from the following description of the illustratedembodiment, that the touch screen 1 belonging to the mobile telephone Tis built around the display unit 3, with a number of light pulseemitting units 4, 4′ orientated at right angles, and a number of lightpulse receiving units 5, 5′ orientated at right angles, said units beingedge-related and surrounding said display unit 3 resting on thesubstrate 2.

For the sake of simplicity, requisite devices and connections to thesubstrate 2, and requisite functions for driving the LCD unit 3 in aknown manner are not shown.

The units 4, 4′ that emit pairs of mutually intersecting light pulsesare adapted to emit short IR light pulses through the medium ofpulse-generating circuits 4 a, 4 a′. One such IR light pulse isreferenced 40 in FIG. 2, where it is shown orientated at a very smalldistance over the upper surface 3 a of the display unit 3.

FIG. 2 shows three light pulse paths 40, 41 and 42, although for thesake of simplicity only the light pulse path 40 will be described in thefollowing description.

The upper surface 3 a shall be capable of presenting a number of graphicsymbols in a known manner.

In the illustrated embodiment, this graphic display is chosen to complywith a chosen menu of a mobile telephone apparatus T.

Although these graphic symbols are shown to consist of digits (FIG. 5)orientated in rows and columns in the case of the illustratedembodiment, it will be understood that a display unit 3 in the form ofan LCD unit can be caused to present a number of other symbols, such asdigits/letters, words, sentences or corresponding graphic symbols,depending on the menu chosen.

FIG. 6 illustrates schematically a number of pulse receiving circuits 5a, 5 a′ coordinated in right angle orientations, said circuits beingadapted to receive signals from light pulses detected by the light pulsereceiving units 5, 5′, said units being referenced 5S, 5R, 5Q . . . 5J,5I in one column, and 5′A, 5′B . . . 5′G, 5′H in one row.

A number of pulse emitting units 4, 4′ in right angle orientation areadapted to emit light pulses via the control from coordinated pulsegenerating circuits 4 a, 4 a′, said column-related pulse emitting units4 being referenced 4I, 4J, 4K . . . 4R, 4S, while the row-related units4′ have been referenced 4′H, 4′G, 4′F . . . 4′B, 4′A.

The pulse receiving circuits 5 a, 5 a′ are of a known kind and eachcircuit is adapted to generate current pulses or voltage pulsescorresponding to the light pulses that are received by correspondinglight pulse receiving units 5, 5′, and to transpose these pulses intosignal information sent to a calculating unit 6.

More specifically, the calculating unit 6, shown in FIG. 6, functions toactivate each of the row-orientated units 4′H to 4′A and each of thecolumn-orientated units 4I to 4S in a chosen order and, at the sametime, open the oppositely located pulse receiving circuits 5 a′ and 5 a.

This means that when the calculating unit 6 activates a light pulseemitting unit 4P during a time slot, the calculating unit 6 will expectsaid light pulse to be detected by the light pulse receiving unit 5Lduring the same time slot.

In such case, the calculating unit 6 allows associated calculatingcircuits, such as circuit 6 a, to take an inactive state.

On the other hand, if the expected light pulse fails to arrive, e.g. isshadowed by a pointer 9, the calculating circuit 6 a is activated.

The calculating unit 6 thus includes a plurality of calculatingcircuits, of which a calculating circuit 6 a is adapted to allow thegeographic position of the point P1 and its related row to be evaluated,depending on the position and the row (or column) of one or moreco-ordinate orientated, light pulse receiving column-related units5S-5I, one of which is referenced 5P in FIG. 6 in connection with thecircuits 5 a, and therewith activate a function that corresponds to thisposition in a chosen menu, via a function-related output signalgenerated on a conductor 6 d.

An output signal of this kind is, of course, more complex than solely anoutput signal. Despite this, the output signal is not shown for the sakeof simplicity.

The calculation performed in the calculating circuit 6 a can beperformed more precisely in order to be able to establish the twoco-ordinates of a chose geographical position of the point P1. Thiscalculation can be based on the orientation of the light pulse receivingunit 5′C and its connection to circuit 5 a′C, by taking into accountalso the light pulse receiving unit 5′C, which receives no light pulseor which indicates a light pulse deficiency, meaning in practice thatboth units 5′C and 5P are shadowed by one single pointer 9 placed at thepoint or surface section P1.

The calculating unit 6 includes a further calculating circuit 6 b thatkeeps an account of the activation of and the sequence assigned torespective circuits within the coordinations 4 a and 4 a′ respectivelyand a light pulse emission from each of the column-related units 4I-4Sand the row-related units 4′H to 4′A respectively, andemission-dependent activation of the individual circuits within theco-ordinations 5 a and 5 a′ respectively and an anticipated reception ofa light pulse in each of the units 5S-5I and 5′A-5′H respectively withintheir allotted time slots.

On the basis of information as to which of the units 5S-5I and the units5′A-5′H should indicate the presence of a light pulse within its timeslot but fails to do so, it is possible to evaluate a position that isrepresentative of the two-dimensional geographic position P1 on theupper surface 3 a of the display unit 3 where mutually intersectinglight rays from the light pulse emitting unit 4L on the one hand and thelight pulse from the light pulse emitting unit 4′F on the other hand,via respective circuits 4 aL and 4 a′F, is shadowed by a narrow pointer9 in point P1, whereby solely those light pulse receiving units 5P and5′C in connection with said circuits 5 aP and 5 a′C are shadowed, whichis thus read in the calculating circuit 6 and causes activation of thecalculating circuit 6 a.

Returning to FIG. 2, it will be seen that the light pulse emittingunits, such as the unit 4L, and the light pulse receiving units, such asthe unit 5P, shall be orientated adjacent said display unit 3, with thedirections of respective light pulses 40 a and 40 b from the pulseemitting and pulse receiving units are at right angles, or at leastgenerally at right angles, to a plane 3 a′ orientated to coincide withthe planar upper surface 3 a of the display unit 3.

The invention also relates to the use of at least two pairs of mutuallyopposite light pulse deflecting devices 7, 8 and 7′, 8′, in practicefour pairs of such devices, said devices being positioned very close tothe display unit 3 and around the edges of said unit, in accordance withthe FIG. 2 illustration.

It will also be seen that the supporting substrate 2 shall not onlysupport a display unit 3 but also the series-orientated light pulseemitting units 4, 4′ and the series-orientated light pulse receivingunits 5, 5′ in the form of a plurality of row-related light pulseemitting and mutually identical units 4, 4′, and a plurality ofrow-orientated light pulse receiving and mutually identical units 5, 5′in mutually equal numbers on both sides of the display unit 3 for directcorrespondence with each other.

The supportive substrate 2 may consist of the telephone circuit board 2′carrying discrete components (not shown).

The substrate 2 is thus not only adapted to support the display unit 3centrally thereon, but also edge-related light pulse emitting units 4,4′ and the oppositely located light pulse receiving units 5, 5′ disposedaround all four edges of the substrate, and also the four mutuallyopposite devices 7, 8 and 7′, 8′ respectively.

The units 4, 4′ emitting said mutually crossing light pulses and saidunits 5, 5′ receiving said mutually crossing light pulses mayconveniently be connected to said pulse generating circuits 4 a, 4 a′and said pulse receiving circuits 5 a, 5 a′ by means of connecting wiresor the like (not shown), said circuits conveniently being attached to orincluded as components in the circuit board 2′.

As will be seen particularly from FIG. 2, the light pulse deflectingdevices 7, 8 may each consist of a mirror unit that has an angled mirrorsurface, where, in such case, the mirror surfaces 7″, 8″ of said mirrorunits will preferably be orientated at an angle of 45 degrees inrelation to a vertical direction of propagation allocated to the lightpulses 40 a, 40 b, to a horizontal direction of propagation 40 over theupper surface 3 a of the display unit 3.

However, FIG. 2 shows that each light pulse deflecting device 7, 8 shallconsist of a three-sided right-angled prism-formed unit, whererespective mirror surfaces 7″ and 8″ of said prism units will obtain theorientation disclosed in the introduction and extend along two rows andtwo columns of the units 4, 4′ and 5, 5′.

The circuit board 2′ may also carry electronic circuits and componentsadapted to perform functions related to a mobile telephone unit and atelephone network to which said unit is connected.

FIGS. 1 and 6 show that said light pulse emitting units 4 are columnorientated and that said light pulse receiving units 5 are also columnorientated, and that the light pulse emitting units 4′ and the lightpulse receiving units 5′ are row-orientated and extend at right anglesto said columns.

Thus, said units are orientated directly in opposing columns and rowswith right-angled orientations there between and at a distance betweensaid rows and columns that only slightly exceeds the dimensions of thedisplay unit 3, as made evident in FIG. 2.

As shown in FIG. 2, the light pulse emitting units, such as the unit 4L,and the light pulse receiving units, such as the unit 5P, are positionedon the sides of the display unit 3 and closely adjacent the mutuallyopposite edges of said display unit, so as to provide a compactconstruction.

As will be seen from FIG. 1, the substrate 2, in the form of a circuitboard 2′ carrying, inter al, a display unit 3, light pulses emittingunits 4, 4′, light pulse receiving units 5, 5′ and fixed componentsnecessary to the function of the mobile telephone unit T, is adapted forfastening to a first casing part 10 of the telephone unit T intended forco-action with a second casing part 11. The mutually co-acting state ofsaid casing parts is shown in FIG. 2.

The light pulse deflecting devices 7, 8, with their respective mirrorsurfaces 7″, 8″, and the light pulse deflecting devices 7′, 8′ withtheir mirror surfaces are disposed along a rectangular raised edge orrim 11 a, included in the second casing part 11 as a replaceable lid orcover, where said rim 11 a is able to co-act with and completely coveran opening with a transparent protective element 11 b, such as a plasticsheet or glass sheet, positioned immediately above the display surface 3a.

FIG. 3 illustrates more specifically a proposed application of thepresent invention, where it is assumed that a pointer 9, a pencil, penor the tip of an index finger, is brought to a position (P1)corresponding to a position P1 on the display unit 3, in accordance withFIG. 6, and that light pulses 40 a emitted by the light pulse emittingunit 4L are shadowed (40) by the tip 9 a of the pointer, whereby thelight pulse receiving unit 5P will not receive any light pulses (40 b)and will indicate, via a pulse receiving circuit 5 aP, to thecalculating unit 6 a light pulse absence within its allocated time slotand cause activation of the calculating circuit 6 a.

In accordance with the FIG. 6 illustration, the calculating unit 6 isthereby able to ascertain that light pulses have been emitted within oneand the same time slot not only by the unit 4L but also by the unit 4′F,and that no light pulse has been received either in the unit 5P or inthe unit 5′C within said time slot, thereby enabling the geographictwo-dimensional position of P1 to be calculated and evaluated andtherewith enabling corresponding information to be sent to the circuitboard 2′ via the conductor 6 d.

FIG. 5 is a schematic plan view illustrating the function shown in FIG.3, and also shows activation of a surface section 12 in the same way asthat earlier described with reference to a narrow pointer 9 and its tip9 a.

The surface section 12 is represented by the number 3, and the displayunit 3 has been allocated a first display surface section 31,represented by the keypad of the mobile telephone apparatus T with itsrows and columns of keys or buttons, and a second display surfacesection 32, represented by the presentation surface of said mobiletelephone apparatus T.

Thus, the possibility of co-ordinating both the first display surfacesection 31 and the second display surface section 32 within one and thesame display unit 3 lies within the concept of the invention.

It should be noted in this respect, with reference to FIG. 7, that amarked surface section, such as a number-presenting surface section 12′,may be diffuse and cover two or more light pulse receiving units, forinstance units 5′B, 5′C, 5′D and 5′E, and four light pulse receivingunits 5Q, 5P, 5O and 5N active against opposing light pulse emittingunits 4′G, 4′F, 4′E, 4′D and 4K, 4L, 4M, 4N respectively, and that acorrect indication may also be obtained even though all of saidreceivers indicate the absence of light pulse related signals or shadowswithin their respective time slots.

In this case, the calculating unit 6 is able to sort out peripheralunits, in the present case the units 5Q, 5N and 5′B, 5′E respectively,with the aid of a calculating circuit 6 c, and therewith deliver aclearer evaluation of the position P1 via the units 5P, 5O and 5′C, 5′D,in accordance with the spot markings in FIG. 7.

FIG. 4 shows a pulse plan applicable to the time-wise distribution ofthe light pulses, said plan being adapted to save energy and to increaseintensity and light strength.

As a result of this pulse structure, each of the light pulse emittingand angled units 4 and 4′ respectively will be actuated solely for ashort period of time and within an allocated time slot.

During the short time slot t0-t1, in which a light pulse emitting unit,such as the unit 4L, is actuated, the calculating unit 6 ascertains, viaan associated pulse receiving circuit 5 aP, whether or not a light pulsehas been received on an oppositely located receiver 5P. The time pointfor said evaluation is referenced t1.

Immediately after the status of the receiver 5P has been read, the lightpulse emitting unit 4L concerned is extinguished at the end of a timeslot t0-t1.

Disturbances that may be caused from ambient light can be suppressed, bytemporarily increasing the intensity of each of the selected light pulseemitting units 4, 4′.

Thus, as will be seen from FIG. 6 in combination with FIG. 7, in respectof conditions where two or more side-related light pulse receiving units5Q, 5P, 5O, 5N and associated pulse receiving circuits indicatesimultaneously the absence of light pulses, the calculating unit 6functions, with the aid of internal calculating circuits, such ascircuit 6 c, to interpret this information to mean that the intendedgeographical position P1 shall be considered to be located between thepoints, or consist of the most probable points, that are representativevia said corresponding pulse receiving circuits.

Thus, FIG. 4 shows that each light pulse emitting unit shall be ignitedover only a short time slot or pulse time, e.g. 10 μs, with an electriccurrent higher than 1A, with a subsequent pause to a time point t2,which may be adapted to more than 100 times the chosen pulse time t0-t1.

Also shown in FIG. 4 is that the emission time or time slot t0-t1 forthe unit 4L begins (t0) slightly before the activated reception time(t1) for the unit 5P, and that an idling time t1-t3 is caused to lapseprior to activation of an adjacent unit 4K within its time slot, whereafter the unit 5Q is immediately activated.

The same applies to the unit 4J and to the unit 5R and also remainingunits, these latter units not being shown in FIG. 4.

With the intention of saving energy, a lower idling time frequency(t0-t2) can be chosen and only one unit, 4L, used. When the light pulseis broken, the display unit 3 is activated via a circuit 62, inaccordance with the FIG. 4 pulse plan.

The light pulse emitting units are activated, via associated pulsegenerating circuits 4 a, 4 a′, sequentially in a consecutive order orare selectively positioned in a predetermined order, and thecorresponding light pulse detecting units 5, 5′ can also be activated insaid predetermined order, via the circuits 5 a, 5 a′.

FIG. 8 shows that a plurality of light pulse emitting units, referenced4J, 4K and 4L, are adapted to send light pulses during a chosen timeduration and during respective time slots, and that only one light pulsereceiving unit 5R is adapted to be activated in this respect, so as toallow anticipated or expected light pulses to be received during saidchosen time duration and within said time slots, and therewith allowoccurring light pulses and shadowed light pulses to be registered so asto enable the geographical position of a more diffuse point, such as thepoint P1′, to be evaluated.

Although not shown, it is obvious that a plurality of light pulsereceiving units 5P, 5Q, 5R could be adapted to receive consecutivelyduring a chosen time duration a plurality of light pulses emitted intime slots from solely one light pulse emitting unit, for instance theunit 4L, and to adapt the light pulse receiving units to be activated toreceive anticipated light pulses during said chosen time duration andtherewith allow occurring light pulses and shadowed light pulses to beregistered.

FIG. 9 shows a more realistic and practical application of theprinciples for activating a “key” or “button” indicated in FIG. 6.

FIG. 10 illustrates a further practical application of the principlesindicated in FIG. 6 for activation of another key or button foractuation of another mobile telephone function.

In this case, the display unit 3 with its upper surface 3 a is actuatedby a surface section of the thumb of the user, namely the thumb surfacethat faces inwards towards the palm of the user's hand, said surfacetherewith covering a large part of the surface section of the uppersurface 3 a.

In this regard, FIG. 9 shows that the surface section of the thumb 90will shadow the column-related units 5R, 5Q, 5P and 5O and also therow-related units 5′C, 5′D, 5′E, 5′F and 5′G, and that the calculatingcircuit 6 c functions to establish the key or button (8) that has beenactuated, from this pattern of shadowed light pulses.

In this respect, FIG. 10 shows that the surface section of the thumb 90will shadow the column-related units 5S, 5R and 5Q and also therow-related units 5′D to 5′H, and that the calculating circuit 6 e isadapted to establish which button or key (6) has been actuated, from thepattern of shadowed light pulses.

The invention has been described with reference to sending short lightpulses in the IR range.

The pulse technique enables stronger or weaker signals to be generatedwith the aid of a calculating circuit 6 f so as to allow energyconsumption and power output to be adapted to special ambientcircumstances, such as sunlight or darkish surroundings.

Because the light pulse emitting units 4, 4′ are ignited during a timeslot of short duration, these units can be overloaded for higher lightintensities without being destroyed.

In the case of a touch screen 1, constructed in accordance with theinvention, it is solely the optical positioning P1 that is measured (nopressure requirement) thereby enabling movement of the thumb along theupper surface 3 a of the display unit 3 to be determined in acalculating circuit 6 g, such as determination of a sign or activationof a telephone function.

For example, the thumb 90 may be moved in a direction from right toleft, so as to activate the “finish/close” function.

The proposed technique provides absolute positioning. This obviates theneed to calibrate the unit.

By setting conditions for what shall be estimated as the measuredposition P1, the technique can be readily applied with a small display(restricted to said surface) as a keyboard.

Because no functional component is required over the display unit 3,there can be used a conventional plastic cover that can be changed whenscratched.

The calculating unit 6 c need not necessarily be adapted to calculate acentre of the pointer, e.g. of the thumb 90. It may, at times, beconvenient to allow the outermost edge or outermost edges of the coveredsurface section to be read.

As will be evident from FIG. 9, orientation of the position P1 can bederived by the units 5′B and 5′H indicating light pulses, whereby theunit 5′E can be considered the most likely in this regard.

The position P1 is derived from the fact that the unit 5O does notindicate light pulses, but that the unit 5N does so.

This is interpreted as meaning that the key or button (8) located at acorresponding height shall be activated.

Correspondingly, FIG. 10 shows that the orientation of position P1 canbe determined by ascertaining that the row-related units 5′D-5′H and thecolumn-related units 5S, 5R and 5Q are extinguished.

This can be interpreted by the calculating unit 6 c as meaning that thekey or button (6) located on a row or at a height shall be activated.

The calculating unit 6 also provides a switch between an inactive stateand an active state, wherein the inactive state provides a light pulsefrequency of about 10 Hz, while the active state provides a time slot of5-26 μs.

A time circuit 6 h provides an automatic switch between these states orfunctions, such that a switch to the inactive state is carried out inthe event of a waiting time of 2-5 sec. after an active state and in theabsence of any actuation.

It will be understood that the invention is not restricted to the aforedescribed exemplifying embodiments thereof, and that modifications canbe made within the scope of the inventive concept illustrated in theaccompanying claims.

1. A touch screen for a mobile telephone, comprising: a display unit onwhich a plurality of keypad characters are displayed; a number of lightpulse emitting units; a number of light pulse receiving units, whereinsaid light pulse emitting units send light pulses over said displayunit, and said light pulse receiving units receive said light pulses;and a calculating unit to disambiguate an intended one of the pluralityof keypad characters, based on a pattern of light pulses emitted by theemitting units that are shadowed by a pointer, as determined fromoutputs of the receiving units, wherein the pattern of shadowed lightpulses substantially completely covers more than one displayed keypadcharacter, by determining which of the displayed keypad characters aresubstantially completely shadow-covered, and by selecting an appropriateone of the substantially completely shadow-covered displayed keypadcharacters.
 2. A touch screen according to claim 1, characterised inthat the light pulse emitting units and the light pulse receiving unitsare orientated adjacent said display unit such as to send and receivethe light pulses in directions perpendicular to, or at least generallyperpendicular to, a planar surface on the display unit; and in thatmutually opposing light pulse deflecting devices are placed close to thedisplay unit.
 3. A touch screen according to claim 1, further comprisinga printed circuit board comprising electronic circuits adapted to themobile telephone, and carrying said light pulse emitting units and saidlight pulse receiving units.
 4. A touch screen according to claim 3,further comprising a telephone casing, wherein said printed circuitboard is fastened to a part of the telephone casing.
 5. A touch screenaccording to claim 1, characterised in that said light pulse emittingunits and said light pulse receiving units are connected to respectivepulse generating circuits and to pulse receiving circuits.
 6. A touchscreen according to claim 1, further comprising mutually opposing lightpulse deflecting devices comprised of a number of mirror surfaces.
 7. Atouch screen according to claim 1, further comprising mutually opposinglight pulse deflecting devices comprised of mirror units, that havemirror surfaces orientated at 45 degrees in relation to a light pulsepropagation direction from said light pulse emitting units.
 8. A touchscreen according to claim 1, characterised in that said light pulseemitting units and said light pulse receiving units are orientated inopposing rows and columns and in mutually perpendicular orientations,wherein the distance between said units only slightly exceeds thedimensions allocated to said display unit.
 9. A touch screen accordingto claim 1, characterised in that the calculating unit disambiguates theintended keypad character as being a character displayed betweenlocations on said display unit representative of the pattern of shadowedpulses.
 10. A touch screen according to claim 1, characterised in thatsaid light pulse emitting units are activated, via associated pulsegenerating circuits, in a predetermined order and during selected timeslots; and in that the corresponding pulse detecting circuits are alsoactivated in said predetermined order and during said selected timeslots.
 11. A touch screen according to claim 1, characterised in that aplurality of light pulse emitting units send light pulses consecutivelyduring a selected time duration; and in that one light pulse receivingunit is adapted to receive the emitted light pulses during said selectedtime duration.
 12. A touch screen according to claim 1, characterised inthat a plurality of light pulse receiving units are adapted to receiveconsecutively emitted light pulses from a light pulse emitting unitduring a selected time duration.
 13. A touch screen according to claim1, wherein at least one substantially completely shadow-covered keypadcharacter is farther away from a designated edge of said display unitthan at least one other substantially completely shadow-covered keypadcharacter, and wherein said calculating unit selects an appropriate oneof the at least one farther substantially completely shadow-coveredkeypad characters.
 14. A touch screen for a mobile telephone,comprising: a display unit on which a plurality of keypad characters aredisplayed; a number of light pulse emitting units; a number of lightpulse receiving units, characterised in that the light pulse emittingunits and light pulse receiving units are orientated adjacent saiddisplay unit such as to send and receive the light pulses in directionsperpendicular to, or at least generally perpendicular to, a planarsurface on the display unit; mutually opposing light pulse deflectingdevices placed close to the display unit, wherein said light deflectingdevices transmit light pulses through cover related sections; and acalculating unit configured to disambiguate an intended one of theplurality of keypad characters, based on a pattern of light pulsesshadowed by a pointer, as determined from outputs of the receivingunits, wherein the pattern of shadowed light pulses substantiallycompletely covers more than one displayed keypad character, bydetermining which of the displayed keypad characters are substantiallycompletely shadow-covered, and by selecting an appropriate one of thesubstantially completely shadow-covered displayed keypad characters. 15.A touch screen according to claim 14, further comprising a casing forthe mobile telephone, the casing comprising a rim for covering saidlight pulse deflecting devices, and being made of a transparentmaterial.
 16. A touch screen according to claim 14, characterised inthat the material of said planar surface is transparent forIR-radiation.
 17. A touch screen according to claim 14, wherein saidlight pulse deflecting devices are disposed along the edge of a raisedrim, for co-action with a replaceable lid or cover, wherein said raisedrim co-acts with a transparent protective plastic or glass sheet.
 18. Atouch screen according to claim 14, wherein at least one substantiallycompletely shadow-covered keypad character is farther away from adesignated edge of said display unit than at least one othersubstantially completely shadow-covered keypad character, and whereinsaid calculating unit selects an appropriate one of the at least onefarther substantially completely shadow-covered keypad characters.